1. Field of the Invention
The present invention relates to an imprint method and an imprint apparatus for transferring and forming a desired pattern (such as lines, and graphic patterns) on the material to be transferred.
2. Description of the Related Art
Attentions have now been focused on imprint methods that are a sort of micro-machining or micro-processing technologies. A typical imprint method is a pattern-formation technique that uses a mold member having a minute concavo-convex structure formed on a substrate surface to transfer that concavo-convex structure to the material to be transferred, thereby achieving full-size transfer of that concavo-convex structure.
For such imprint methods, for instance, there has been a photo-imprint method or a thermal imprint method known in the art. In the photo-imprint method, for instance, a photo-curing resin layer having fluidity is located as the material to be transferred on a substrate surface, and a mold having the desired concavo-convex structure is engaged with that resin layer. In this state, the resin layer is then irradiated with light from the mold or substrate side to cure the resin, after which the mold is peeled off the resin layer so that the concavo-convex structure (concavo-convex pattern), where the concavities and convexities the mold has are inverted or flipped over, is formed on the resin layer that is the material to be transferred. In the thermal imprint method, a thermoplastic or thermosetting resin is used instead of the photo-curing resin. When the thermoplastic resin is used, the resin is softened by heating into a fluid state, and the mold is then engaged with the fluid resin to fill the resin up in the concavo-convex structure on the mold, after which cooling is carried out to pull the mold off the resin. For the thermosetting resin, heating is used as the means for engaging the mold with it and curing the resin filled up in the concavo-convex structure on the mold.
Thus, the imprint methods comprises the step of feeding the resin material that is the material to be transferred to the substrate surface, the step of filling the resin up in the concavo-convex structure on the mold, the step of curing the resin layer, and the step of peeling the mold off the resin layer.
For the step of peeling the mold off the resin layer among these steps, there is a technique demanded that enables the mold to be impeccably peeled off the resin layer while the morphology of the transferred resin concavo-convex structure (concavo-convex pattern) is kept intact. In general, a risk of inconvenient deposition of the resin that is the material to be transferred onto the mold, and a risk of mold breakdowns has correlations with the peeling force necessary for peeling: it would appear to be that the stronger the peeling force, the heavier the risks of deposition and breakdowns are.
A method of forming a releasing layer containing a fluorine component or the like on the concavo-convex surface of the mold has been proposed for use with the technique for achieving the aforesaid impeccable peeling (for instance, see JP(A) 2007-326367). In order to reduce drastic fluctuations of surface area rates, there has also been a method put forward, in which a dummy template pattern is formed to prevent the release rate from increasing drastically, thereby reducing the occurrence of defects (for instance, see JP(A) 2010-225683).
However, although the method of providing the releasing layer on the concavo-convex surface of the mold is very effective for where the area of contact of the mold with the resin layer is limited, it is to be understood that when the area of contact grows large for the purposes of boosted-up productivity or the like, the force necessary for peeling grows much stronger, so the simple provision of the releasing layer would be far away from the solution of a problem with peeling. Further, the prior art does not teach anything specific about any possible method that enables peeling with much less peeling force so as to avoid the occurrence of inconvenient deposition onto the mold of the resin that is the material to be transferred.
The aforesaid method of forming the dummy template pattern would also be far away satisfactory because even a portion of the pattern inessential in itself is transferred to the degree that such a peeling pattern has an adverse influence on later steps.
Having been accomplished with such situations in mind, the present invention has for its object to provide an imprint method that includes a specific peeling means that enables peeling with much less peeling force depending on the morphology of the material or material layer to be transferred thereby avoiding the occurrence of inconvenient deposition onto the mold of the material or material layer to be transferred.